Construction of the expression vector pPIC9-α-M, A) schematic diagram of the expression vector pPIC9-α-M; B) PCR amplification of mds I gene from pAO815α-M, molecular marker (lane 1), mds I gene (lane 2); C) dentification of pPIC9-α-M by enzyme digestion, molecular marker (lane 1), pPIC9-α-M digested by EcoR I and XhoI (lane 2) and circle plasmid pPIC9-α-M as control (lane 3).